Medecins Sans Frontieres (MSF), the medical aid agency, is spraying the camps in an attempt to kill mosquitoes.

But there is a shortage of mosquito nets and the government's failure to provide adequate medical supplies and effective drugs is a cause of frustration.

As Christine Schmitz, head of the MSF mission in Uganda, said: "It's a very tragic situation in a country like Uganda which is not a failed state, which is not in a full-blown civil war, which has very well trained Ugandan medical staff, which has drugs and resources available and loads of donors and NGOs who are happy to assist."